People don't get convicted for doing bad things. They get convicted for breaking specific laws. In this case, the laws against defrauding investors were clearly broken, to the extent that a jury unanimously agreed they were broken. Whatever laws might have applied to the patients did not meet that bar.

I keep seeing a lot of "throw them in jail" posts here on HN and it's bad. It should be very hard for the state to jail someone. It should require extremely solid proof that they committed a crime which was defined in law. If we lose that principle, we revert from rule of law to rule of judges and mob rule. Some people like Holmes don't get punished in a way that satisfies everyone they hurt, and people like SBF might never get punished, and that's fine because lowering the burden of proof would only result in more injustice.